Design and Control Strategy of Galvanic Isolated Two-Stage Power Supply for Motor Drive

This paper provides the design and control strategy to achieve high efficiency for a two-stage converter as the voltage source for the motor drive. The proposed design procedure is based on matching the load profile as well as the maximum power limit by the motor. The front-end LLC provides the galvanic isolation capability and high transfer efficiency, while the back-end buck converter provides voltage step-down ability for an extended output voltage range. To further improve the efficiency under different voltage and current profiles, a special control strategy with high efficiency is proposed for a two-stage LLC-Buck converter. Finally, a 200W prototype circuit with both simulation and experimental results is provided to prove the feasibility of the proposed design and control strategy.